Restoration of ecosystem functions: seed production in restored and ancient grasslands

Questions Evaluating seed production as a community function in species-rich temperate grasslands, we asked: (1) Do ancient and restored grasslands differ in the composition of seed-producing species? (2) Do seed-producing species of ancient and restored grasslands differ in their functional traits and habitat origin of their species? (3) How does seed production change during the season considering management; is seed production different for the whole community and for the subset of species occurring in both types of grasslands? Location White Carpathian Mts. (Czech Republic). Methods We assessed the species composition of flowering and fruiting species and collected propagule samples from three ancient and three restored grasslands. From the measured parameters, we estimated seed production for particular fruiting species. We combined these reproductive parameters with data on plant traits and plant status. Results Flowering species in restored grasslands produced three times higher seed numbers and three times lower seed mass than flowering species in ancient grasslands. At ancient sites, most seeds belonged to meadow specialist species; at restored sites, seeds of ruderal and generalist species prevailed. Prior to mowing, in both grassland types the seed producing species were characterised by a high capability of clonal reproduction, high leaf dry matter content, and wind pollination. After mowing, seed producing species were insect-pollinated species at ancient sites. This reflects dominance of grasses before mowing and forbs after mowing. Conclusions Higher seed number, lower seed mass and lower reliance on pollinators in restored grasslands indicate a different ecosystem functionality related to these parameters, in comparison with ancient grasslands. Specifically, seeds act as source for generative regeneration of resident species while resources for pollinators and seed herbivores are reduced. This maintains a differentiation of restored and ancient grasslands not only in terms of species composition but also in their effect on other trophic levels.